Saw frame



K. H. LENK SAW FRAME Nov 6, 1945.

Fired Ma'rch 4, 1944 Patented Nov. 6, 1945 SAW FRAME Kurt H. Lenk, Worcester, Mass., assignor to Parker Manufacturing Company, Worcester, Mass., a corporation of Massachusetts Application March 4, 1944, Serial No. 525,046

2 Claims.

This invention relates to saw frames and the object is to provide a frame of simple and rugged construction which permits the blade to be quickly inserted in the frame and brought to the proper state of tension and as quickly released therefrom. The frame may be similar to those commonly used with hack saws and thus generally of U shape with a manipulating handle at one end, and for purposes of illustration there is shown in the accompanying drawing and will hereinafter be described by way of example a construction of such frame suitable for a hack saw. In the drawing:

Fig. 1 is a side elevation of the frame with the blade in place;

Fig. 2 is a view of the handle end of the frame with parts broken away;

Fig. 3y is a view similar to Fig. 2 showing the parts in another position of adjustment to permit the blade to be removed from the yframe or inserted therein;

Fig. 4 is a section on the line 4-4 of Fig. 1 on an enlarged scale; and

Fig. 5 is a fragmentary section on the line 5-5 of Fig. 4.

Referring now to the drawing and more particularly to Figs. 1 and 2, the frame there shown resembles the conventional hack saw frame of U-shaped form and it may be of adjustable length to accommodate blades of different lengths, and the portion at the left of the gure is herein shown as comprising an angular member of flat metal of suilicient width to provide the desired rigidity having a depending arm 6 with studs 8 carried thereby and extending at right angles one to another, to which the forward fend of the blade may be secured either to lie in the plane of the frame or at right angles thereto. This angular member comprises also the horizontal portion I -forming the forward portion of the back of the frame which telescopes into a channel member I2 forming the cooperating portion of the back and wherein it is secured in the desired position of adjustment by any suitable or usual means, as, for example, the cross-pin I4 shown adapted to engage the notches I6 in the arm I 0.

The flanges I8 of the channel I2 toward the right of the frame are extended downwardly to provide cheek portions 2U between the lower parts of which is pivoted on cross-pin 22 an arm 24 having at its lower end the studs 26 to engage the end of the blade. When this arm is held in the position of Fig. 2, it holds the blade under the desired tension. If released so that it is free to swing clockwise to the position of Fig. 3, the blade may easily be removed from the studs 8 and 26 or a blade placed in position on such studs.

To control the positionof the arm 24 the upper end thereof above the pivot 22 is formed as a follower adapted to cooperate with a member 2B in the nature of an edgecam received between the cheeks 20 and turning on the cross-pivot 30. This member also embodies an arm 32 extending to the exterior of the framev to provide anoperating handle for the cam which herein is also the manipulating handle by which the saw is operated in use and is shown as of the piston grip type with the grip 34 for encirclement by the grasping hand. The member 28 comprises a convex edge portion 36, preferably a circular arc, which, however, is centered at a point 38 (see Fig. 2) diierent from the pivot point 30, the relation to the pivot being such that the highest point of the eccentric or cam edge thus formed is at the lower right-hand side in Fig. 1, the edge receding inwardly therefrom towardv the pivot 30, and this edge 36 is adapted to fit, in the position of the parts shown inliig. 2, a similar concave circular g edge portion 40 of the upper end of the arm 24 to retain the arm in the position shown, as Will hereinafter be more fully described.

Counterclockwise movement of the handle is limited by engagement of the arm 32 with the web of the channel I2 and engagement of the nose 44 at the upper end of the follower surface 40 with v the cam then limits clockwise swinging movement of the arm 24. In the position of parts shown in Fig. 2 the arm is free to swing counterclockwise away from the cam and for convenience to `prevent its swinging too far and coniine it near its positions of use I may provide a stop 45 extending between the anges I8 and cooperating with a surface at the left hand end of the arm 2'4 in the manner illustrated in Fig. 2.

To lock the parts in the position of Figs. l and 2 with the blade under tension I provide a. releasable latch or detent for interlocking the cam and its follower surface, the latch in the embodiment shown being in the form of a sliding bolt 48 carried by arm 24 and projecting in intersecting relation to surface 4I] to engage a keeper provided by a groove 46 in cam 28, the groove having abrupt shoulders at top and -bottom to engage the sides of the bolt. To accommodate the bolt the upper portion of arm 24 may be extended to the left in the gures, this extension being received between the depending flanges I8 of the back I2 of the frame. In the upper portion of the arm including this extension I have shown a slot 41 crossed at its right-hand extending rearwardly from the bolt and passing through an opening in the wall at, the rear of the slot. The bolt 48 lies flush with the nearer surfaces, viewing Figs. 2 and 3, of the arm 24 and the cam 28.

To provide for retraction of the bolt a pin 54 may project therefrom through an ,opening 56 (see Figs. 4 and 5) in the flange I8 of the channel and carry at its outer end a button or thumb piece 58 for engagement by the Viinger. Herein I have shown a thumb piece at one side ofthe frame only. Since this button or thumb piece moves with the arm 24 the opening 56 may be made, as seen in Fig. 5, to permit not only rectilinear movement of the pin 54 when the button is moved to the left in Fig. 1 but swinging movement with the arm 24 when the latter moves to the position of Fig. 3 and the reverse movements. The button 5S is desirably of suchsize as to overlie and conceal the hole 56 in all positions of the former.

Assuming now that the parts 'are in the position of Fig. l and that it is desired to release the blade, the button 58 is pressed toward the left in the figures to retract the bolt or detent 48 from the groove 46 and the handle is thenv rocked upwardly, counterclockwise in the figures, releasing arm 24 which may swing to the position of Fig. 3 to permit the blade to be taken off. Assuming that the saw is held in the right hand, the button may be manipulated with the left hand, if desired, but a little experience permits the operator to press it with the extended thumb of the hand which grasps the handle 34. The blade may then be easily removed from the studs 8 and 26 and its orientation altered or a new blade substituted.

After the blade has thus been positioned on the arms, the handle 34 is swung downwardly and the eccentric surface 36 then acts on the upper end of the arm in the manner of an edge cam, swinging the arm to the position of Fig. 2, when the bolt 4B under the inuence of the spring snaps over into the groove and locks the parts together in the manner illustrated in Fig. 2. In bringing the parts to this position an adequate tension is placed on the blade. The arm is securely held by virtue of the extended contacts of the two circular arcs 36 and 40 in the position of Fig. 2.

The present application is subsidiary to my companion application, Serial No. 525,045, filed concurrently herewith, and wherein claims have been presented generic to the disclosures of both applications.

I am aware that the invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof, and I therefore desire the present embodiment to be considered in all respects as illustrative and not restrictive,.as is in fact clear in several matters from the description itself. Reference is to be had to the appended claims to indicate those principles of the invention exemplified by the particular embodiment described and which I desire to secure by Letters Patent.

I claim:

1. A saw frame comprising a main portion having spaced ilanges, an arm pivoted between said flanges and having a portion projecting therefrom provided with means for anchoring a blade, a member also pivoted between said flanges and having an operating portion projecting therefrom, said member having an eccentric edge portion opposing'the edge of the upper portion oi said arm to cam the same to blade-tensioning' position, said arm and member one carrying a' retractible bolt and the other a cooperating keeper in the zone of said opposed edge portions for interlocking engagement when the camv brings the arm to blade-tensioning position.

2. A saw frame comprising a main portion having spaced flanges, an arm pivoted between said iianges and having a portion projecting therefrom provided with means for anchoring a blade, a member also pivoted between said flanges and having an operating portion projecting therefrom, said member having an eccentric edge portion opposing the edge of the upper portion of said arm to cam the same to blade-tensioning position, the upper portion of the arm being shaped to iit the opposed cam surface of said member over an extended length when in said position, said arm and member one carrying a retractible bolt and the other a cooperating keeper, in each instance within the interfltting areas, for interlocking engagement when the member brings the arm to blade-tensioning position.

KURT H. LENK. 

